Cathode ray tube



sept. 2s, 1943. M. MESSNER Y 2,330,604

CATHODE RAY -TUBE Filed Oct. 10, 1941 Patented Sept. 28, 1943 cATHoDE RAY TUBE Maximilian Messner, Berlin, Germany; vested in the Alien Property Custodian Application October 10, 1941, Serial No. 414,411

In Germany April 26, 1940 (Cl. Z50-164) 2 Claims.

Cathode ray tubes are known which are provided with scales or coordinate systems or the like in order to serve as a measuring equipment. In prior devices the scales or coordinate systems are arranged in front of the tube or painted on the bulb thereof. These arrangements are defective inasmuch as parallactical errors in observation may arise, especially if the glass of which the bulb consists is of a certain thickness.

The invention has for its object to overcome this drawback and consists in certain features of novelty which will appear from the following description and the accompanying drawing,A in which Fig. 1 is a sectional view showing one embodiment of the invention,1ig. 2 is a plan View of the .arrangement represented in Fig. 1.

The bottom 2 is surrounded with an annularl casing 4 in which vglow lamps 5 are arranged to illuminate the bottom 2 by rays entering itlaterally, whereby the drawing 1, 8 or any other representation will be distinctly visible, the casing 4 preventing the lamps 5 from shining in other directions. Y

Preferably, the light enteringthe bottom 2 is given a colour diiferent from the colour of the light emitted by screen 3. This expedient will add to the visibilityof the drawing in the bottom 2. Y

What is claimed is:

1. A cathode ray tube having a translucent end wall, a scale on the inner side of said wall, a fluorescent screen at said end wall, and illuminating means to illuminate said end wall exclusively in a direction laterally thereof.

2. A cathode ray tube according to claim 1 in which a casing prevents rays from said illuminating means from reaching said end wall from other than said lateral direction.

MAXIMIHAN MEssNER. 

